XTC Questions

[braintheory]

So I currently have a Bogner XTC 101B (and a bunch of other amps). I've had this amp now for 4 years and I find the red channel to be too dark, way too compressed, and not enough aggression, and the blue channel to also be too compressed and also not enough aggression. I've tried the XTC Classic and thought it was much better and fixed many of my complaints about the 101B (and had a way better clean channel), but am still not sure if it was aggressive enough for my tastes. My first question is how does the 20th anniversary model compare and will it satisfy my needs? A lot of people say that the 20th anniversary model is the best XTC ever.

My second question is if there are basic mods I could do to make the 101B sound like the 20th Anniversary. And when I say basic I mean something like change tubes, capacitors, or resistors, etc. (Nothing more involved than that) I've heard that the 101B with kt88's actually sounds very similar to the 20th Anniversary and also addresses most of my complaints.

My last question is why do some say that the blue channel on the 101B is the best blue channel of all XTC's? I thought the blue channel on the Classic was much better (more open, aggressive, organic, and nuanced).

 

[_actual time_]

a couple quick suggestions (more details later when i have some time

-consider the R19 mod, to resistor #19. it affects both Red and Blue. it adds upper-mids, which might get you more aggression. but it also adds some gain and so might sound more compressed to you. it if used in unboosted mode might get toward what you want.

-if you play a lot on unboosted Red and Blue, consider cutting out C224, near V2 on the circuit board. it reduces the high-end in unboosted Red and Blue. without it, they are noticeably brighter.

-and, read all of Setneck's posts and study them meticulously. he knows the amp thoroughly, including what some of the changes were between the 101B and the 20th.

if you search this sub-forum, there are posts and threads about both of those mods, many of them by Setneck.

 

[jamme61]

Set neck is the man for all bogner xtc mods

 

[pedal builder]

if you cut both out would'nt that possibly be too bright ? and what does c224 do ?

 

[jamme61]

try to read some of the posts by setneck. He goes into great detail about these mods and what they do.

 

[Setneck]

So I currently have a Bogner XTC 101B (and a bunch of other amps). I've had this amp now for 4 years and I find the red channel to be too dark, way too compressed, and not enough aggression

101B isn't easy amp to setup and dial. It isn't "plug'n'play" amp, it needs working on it quite extensively. You could dial it to be more open though.
If You don't want to mess with the circuit - try setting Presence, dirty Middle and Treble around 2 o'clock, dirty Excursion to M or T and Pre-Eq to B1. Don't set Red Gain beyond noon.

As I've already written - C40 Excursion cap, audio dirty Treble pot and 25K Presence pots and 100nF PI output caps are mainly responsible for "blanket effect". Those mods would be enough to make a tone more in-front and cutting.

My first question is how does the 20th anniversary model compare and will it satisfy my needs? A lot of people say that the 20th anniversary model is the best XTC ever.

20th Ann is revoiced quite heavily, with Classic filtering. It is more open and less compressed.

My second question is if there are basic mods I could do to make the 101B sound like the 20th Anniversary. And when I say basic I mean something like change tubes, capacitors, or resistors, etc. (Nothing more involved than that)

Well, I don't think that You might do that. Although 20th Ann is being made using 101B pcb but there are many different mods and tweaks, some of them surely placed under the pcb. You would have to have 20th Ann on bench to mimic it on Your 101B. If You're not satisfied with Your 101B You might have to consider buying 20th Ann I'm afraid.

You may make 101B more open using some of my mods, but it will still sound different than 20th Ann.


Regards, Andy

 

[Setneck]

if you cut both out would'nt that possibly be too bright ? and what does c224 do ?

It won't be too bright. It'll become more open and cutting. C40 Excursion cap muddies a tone horribly, wish that removing that cap was first mod I have done to my amp. Cut it out and see for Yourself that You're not gonna miss it. I got it on switch now, which I'm going to surely remove next time I'll visit Marvel Amps HQ.

As Jamme said, C224 kills high frequencies when in unboosted mode. It is in parallel with a 100K resistor which lowers a value of 500k 2nd stage grid resistor. Bare resistor simply drops the gain down, not messing with the tone. 1000pF cap is added to shape the tone more towards lower freqs.

Regards, Andy